The present invention relates to resin compositions, and specifically, it relates to resin compositions which are useful for obtaining various molded articles that require impact resistance at low temperatures, and to molded articles composed of the resin compositions.
Known methods for increasing impact resistance at low temperatures of molded articles each composed of a thermoplastic resin include a method in which various elastomers (rubber components) are blended with the thermoplastic resin, a method in which a plasticizer is added to the thermoplastic resin, a method in which the aforementioned two methods are combined, and a method in which a thermoplastic elastomer is used.
However, even if any of these improvements is performed, the resulting molded articles have insufficient impact strength at low temperatures in some applications. As a solution to this problem, one skilled in the art uses large amounts of various elastomers or adds a plasticizer to the resin to the limit of compatibility with the resin. However, the use of large amounts of elastomers invites deteriorated characteristics of the resin, such as strengths (e.g., tensile strength and flexural strength), heat resistance and chemical resistance. The addition of large amounts of plasticizers causes bleeding of the plasticizers.
Accordingly, an object of the present invention is to provide a resin composition which can have substantially improved impact resistance at low temperatures, while maintaining its tensile properties, flexural properties and heat resistance properties, and to provide a molded article composed of the resin composition.
After intensive investigations to achieve the above objects, the present inventors have found that the incorporation of a glycol or its derivative into a thermoplastic elastomer can substantially improve impact resistance of the resulting molded article at low temperatures, without deterioration of the characteristics of the thermoplastic elastomer (e.g., tensile properties, flexural properties and heat resistance properties). The present invention has been accomplished based on these findings.
Specifically, the present invention provides a resin composition including a thermoplastic elastomer and a glycol or its derivative.
In addition, the present invention provides a molded article composed of the aforementioned resin composition.